The present invention relates to an improved sieve or screen for sifting stones and gravel from garden soil by gravitational means. The new garden sieve may also be used for sifting fine sand from coarse sand and/or gravel or for separating any fine granular product from coarse granular product. Prior art sieves are exemplified by U.S. Pat. Nos. 1,629,149, Citrin; 1,510,742, Gutleben; and 1,424,451 Crandall.
The typical garden sieve consists of a fiat rectangular frame, typically made of wood, with a wire screen or mesh affixed to the underside. Its principal use is to remove stones and gravel from garden soil in small quantities. It is utilized by propping it at an angle or setting it on a frame above the ground. The work of sifting stones from garden soil is laborious and time consuming. In known fashion the rectangular frame is placed at an angle to the ground with one end elevated and supported by a vertical brace. The gardener shovels or deposits garden earth aggregate against the screen in order that as the aggregate hits the screen the finer soil material will sift through and the larger stones will roll to the ground in front of the screen. In practice, as the angle of the sieve is increased, the effectiveness of the screen decreases as most of the material will fail to separate. Conversely, as the angle is decreased from the vertical, more fine material will separate on each shovelful, but the coarser material fails to move to the lower end of the sieve and thus impedes separation. Large soil processing equipment designed for processing of far larger quantities than that contemplated herein exists but it is uneconomical, impractical, and unsuitable for typical home garden use.